1. Field of The Invention
The invention relates to a sliding contact member or article which is electrically conductive and capable of carrying high current densities, such as brushes for engine starters and slippers for pantographs of electrical trolleys or subway transport systems. More particularly, the sliding contact member according to the present invention is based on copper and carbon, and includes at least one added material which is a metal or a metal alloy having a melting temperature which lies significantly below the melting temperature of copper.
2. Background of The Art
Examples of sliding contact members include carbon brushes employed, for example, for engine starters, as well as slippers, for example, for pantographs of electrical trolleys or subway transport systems.
Conventional sliding contact members frequently include lead or antimony additives. The purpose of such additives is to provide a good cleaning effect, to promote cooling of the contact spots of the sliding contact member during operation, and to provide good slidability against a mating contact member. However, these known additives are toxic and damaging to the environment.
It is therefore an object of the present invention to provide a sliding contact member which does not contain any significant amounts of lead or antimony, but whose operating characteristics are not adversely affected.